Merge pull request #113 from shreyasminocha/pubkey-ble-conversion

Add BLE ad data generation method

Author: malmeloo

findmy/keys.py

@@ -74,17 +74,43 @@ def adv_key_b64(self) -> str:
         """Return the advertised (public) key as a base64-encoded string."""
         return base64.b64encode(self.adv_key_bytes).decode("ascii")
 
+    @property
+    @override
+    def hashed_adv_key_bytes(self) -> bytes:
+        """See `HasHashedPublicKey.hashed_adv_key_bytes`."""
+        return hashlib.sha256(self.adv_key_bytes).digest()
+
     @property
     def mac_address(self) -> str:
         """Get the mac address from the public key."""
         first_byte = (self.adv_key_bytes[0] | 0b11000000).to_bytes(1)
         return ":".join([parsers.format_hex_byte(x) for x in first_byte + self.adv_key_bytes[1:6]])
 
-    @property
-    @override
-    def hashed_adv_key_bytes(self) -> bytes:
-        """See `HasHashedPublicKey.hashed_adv_key_bytes`."""
-        return hashlib.sha256(self.adv_key_bytes).digest()
+    def adv_data(self, status: int = 0, hint: int = 0) -> bytes:
+        """Get the BLE advertisement data that should be broadcast to advertise this key."""
+        return bytes(
+            [
+                # apple company id
+                0x4C,
+                0x00,
+            ],
+        ) + self.of_data(status, hint)
+
+    def of_data(self, status: int = 0, hint: int = 0) -> bytes:
+        """Get the Offline Finding data that should be broadcast to advertise this key."""
+        return bytes(
+            [
+                # offline finding
+                0x12,
+                # offline finding data length
+                25,
+                status,
+                # remaining public key bytes
+                *self.adv_key_bytes[6:],
+                self.adv_key_bytes[0] >> 6,
+                hint,
+            ],
+        )
 
 
 class KeyPair(HasPublicKey):